Comment 55 for bug 164640

(In reply to comment #5)
> 1. Discard the fontconfig configuration of this value, use the freetype
> constants, and load the configuration from the X resource database, handling
> the string constants in cairo. This is the only method working now anyway.
>
> 2. Figure out how to get the fontconfig object registration working even with
> pango, moving all constants and configuration to cairo.

I'll let Keith pronounce if this is feasible. Possibilities I see:
* reparse the configuration file after the constants have been registered (not sure fontconfig allows this, not so nice for performance).
* introduce a cairo_init() method that cairo consumers have to call before touching fontconfig (adds burden/incompatibility to cairo users).

Otherwise, there is a third possibility: Keep this parameter in fontconfig and change cairo to take it into account, as this is done for antialiasing, subpixel order or hinting.

I'm questioning having such an option at all, see http://lists.cairographics.org/archives/cairo/2008-January/012685.html